Like CyGho says, CDEX all the way. It is freeware and it includes the LAME mp3 encoder (also freeware).
And as we all know, LAME is the best encoder available at this time. Sounds much better than any other encoder - AudioCatalyst uses the Xing encoder, which is 3rd-rate, and MusicMatch uses a crippled, substandard version of the Fraunhofer encoder.